Null point

Dear,

 Null point in kiln hood  and cooler not changed when ph flow,cooler fan flow and vent fan flow constant.

 Null point shift if any one can changed. if ph flow increased and both keep  constant than null point shift toward kiln side.

 null point may be shiftted if cooler last fans flow changed and keeping same ph and cd fan flow toward to cooler discharged.

 But any condition if we control constant hood draft in kiln hood than null point never shift.

 tech forum